Most, if not all commercially available power and sail boat hulls of 25 feet or more are designed around a frame of ribs and stringers, covered on the outside with a non-porous skin of fabric, wood, metal, fibrous reinforced plastic (FRP) or other non porous material. Examples range from a birch bark canoe to the modern aircraft carrier. Historically boat construction begins with the building of a keel to which ribs and parallel stringers are attached. The outer water proof skin is then attached to the ribs and stringers. In modem fiberglass construction the outside skin, in the form of a resin impregnated fibrous cloth, mat or spray chopped strand is applied to the inside walls of a mold and then a grid system of longitudinal stringers and full width or stud ribs is bonded to the inside of the skin. In both cases the rib and stringer system is the structural strength of the resulting boat hull shell.
Ribs are evenly spaced, parallel, side to side primary structural members to which are fastened or bonded the hull skin. Ribs maintain the beam, shape and strength of the hull's cross section, preventing it from collapsing inward when under load stress.
Stringers are primary longitudinal structural stiffening members placed parallel to each other and running from the bow to the stem of the boat. All stringers do not always run the entire length of the boat. To the stringers are fastened or bonded the ribs and hull skin. Stringers supply strength to the length of the hull preventing it from bending from bow to stem, like a fishing rod, when under load stress. When combined together this rib/stringer system is the primary strength of the hull, without which the hull would be unable to hold its design shape when under way in heavy seas.
All of the known mid sized and larger boat hull building systems require some form of rib/stringer system for their primary hull strength on a longitudinal and horizontal axises. All of the known power and sail boat hulls above 25' in length would not be sea worthy if the rib/stringer system was removed.
Some small specialty boat have been molded by the rotary molding method as described by U.S. Pat. No. 5,458,844 where in a simple inner liner or shell with stringers, i.e. longitudinal stiffeners, are integrated into the shape of the inner liner and attached by some method to the molded hull. In U.S. Pat. No. 5,458,844 " claim #1 column 6 lines 37 to 39 states ". . . at least one of said moulds being shaped to create a stiffening member in a shell structure formed in said moulds", and column 6 lines 7 to 14, "By forming a hull of a boat as an integral unit with one or more internal stiffening members formed homogeneously with inner or outer shells of the hull, a reliable hull structure can be achieved overcoming problems of failure at joints inherent in conventional designs with bonded or mechanical joining methods. In other words this patent is a method of attaching the "internal stiffening members" so that a ". . . reliable hull structure can be achieved overcoming problems of failure at joints . . . ". The Geiger invention require no "longitudinal stiffening member" in the hull. In rotary molding, both hull and inner liner are normally made of the same material and bonded together by melting (welding) the plastic material together. U.S. Pat. No. 5,458,844 is a variation of the more common practice of mechanically fastening or bonding two rotary molded part together, where in the interior part is shaped in such a way that the required longitudinal stiffening members are incorporated in and made part of the hull or inner liner's shape as clearly illustrated in FIG. 2 item Nos. 28, 29 and 30.
The rotary molding method is adequate for dingy, canoes, kayaks, small sail boats, small outboards or "Jet Skies" etc. but totally impractical for large sea going vessel where twin 1,000 hp to 5,000 hp diesel engines that can weigh over 20,000 pounds each are common. In addition the rotary molding method pre-supposed a very simple interior, not one that incorporates multiple bed rooms, heads, dinning areas and other highly finished living areas. In addition it is unlikely that a mold 100' long by 25' wide by 15' deep that incorporates a lavish yacht interior or complex work boat or military boat interior could be built into a rotary mold, evenly heated and rotated in the manor required for rotary mold manufacturing.
Several other U.S. Patents have been issued that apply to commercial fishing boat arrangements such as U.S. Pat. Nos. 4,033,280 and 4,729,334. However, these Patents are for interior fishing boat deck, cabin shape and space arrangements not for hull structural design. The only places in U.S. Pat. No. 4,729,334 that hull structure is even mentioned are: column #4 lines 8 to 13 where the inventor states that ". . . although wood or metal, such as aluminum may be used in fabricating the hull, deck and cabin a fiberglass reinforced synthetic resin over a wood or metal frame is generally preferred", and column 4 lines 16 to 19 ". . . it (hull, deck and cabin) can be fabricated readily using relatively inexpensive molds and simple hand lay-up or spray-up methods "well known in the boat building industry." In other words the inventor envisions that the boat will be built using present day techniques that are "well known in the boat building industry". The only boat structural design system that is "well known in the boat building industry" today requires the installation of ribs and stringers for hull structural strength which is the ". . . the wood or metal frame . . . " that is mentioned in column #4 lines 8 to 13.
The Geiger invention is an alternative method of boat design and construction that overcomes the requirement for a horizontal and longitudinal structural support system of ribs and stringers, by building a very ridged non-flexible hull shell out of composites, consisting of a fibrous reinforced plastic skins bonded on either side of a light weight core material, then fastening or bonding the normally required decks, bulkheads, cabin sole, interior walls and cabinetry to this hull in such a way as to make the need for an dedicated internal structural system of horizontal and longitudinal stiffeners, i.e. ribs and stringers, unnecessary. At the present time a number of coring materials are available. Among them are cross-link foam such as Divinycell, linear foam such as CoreCell, end grain balsa, and honey comb make of aluminum, plastic or Nomex. A relatively thick laminate of carbon fiber or a very thick fiberglass laminate could produce a non-cored shell ridged enough to be use with the Intra-Bonding Structural Design System.